mckechnie



l. MCKECHNIE.

INJECTI'ON 0F LIQUH) FUEL IN INTERNAL COMBUSTION ENGINES.

APPLICATION FILED AUG.5| 1913.

l, l 93,909. Patented Aug. 8, 1916.

.2 SHEETS-SHEET l.

!llllll Illia/114g J. IVICKECHNIE.

INJECTION 0F LIQUID FUEL IN INTERNAL COMBUSTION ENGINES.

v APPLICATION FILED AuG.5, |913.

1,193,909. I Pat-endAug. 8,1916.

2 SHEETS-SHEET 2.

/ INvIERIToR ,j Mw Z@ @ma f lpowers maybe obtained.

JAMES MQKECHNIE, 0F BrBROw-INFURNESS, ENGLAND, .SSIGNOR T0 VICKEBSVI'iIlflilIlITE'lD, 0F IBABRGW-IN-FUIBNESS, ENGLAND..

INJECTION OF LIQUID FUEL IN INTERNAL-COMBUSTIO ENGINES.

Specification of Letters Patent.

Patented Aug. 8, Igi.

Application filed August 5, 1913. Serial No. 783,054..

To all 'whom t 'may concern.'

Be it known that I, JAMES McKEoHNm, a subject of the King of GreatBritain, residing at Naval Construction Works, Barrow-in-Furness, in thecounty of Lancaster, England, have invented certain new and usefulImprovements inV the .Injection of Liquid Fuel 'in Internal-CombustionEngines', of which the following is a-speciiication.

'This invention relates to the injection of liquid fuel at extremelyhigh pressures into the cylinders of 'internal combustion engines of thetype in which the fuel is ignlted as it enters the cylinders, the chiefobject of the invention being to insure the injection of such fuelunmixed with air at a pressure which is the same for varying fuel supplyand engine power, so that a greater range of power and increased economyat low According to my invention the fuel is injected by the directaction of a pump the plunger of which has 'a stroke capable of pumping alarge excess of fuel and the high pressure desired at the period ofinjection is attained gradually during the idle portion of the pumpcompression stroke, by exercising an increasing choking action'on' theescape of the excess fuel, which choking action is conveniently producedby mechanically operating the suction valve so that it closes slowlyduring the first part of the said compression stroke. The fuelpressure-.iis by this means steadilypraised while the valve is slowlyclosing, the final portion of the pump stroke, with the valve closed,being arranged to give a fuel charge only slightly in excess ofthe fullcharge required. The gradual increase of pressure up to the maximumavoids any sudden shock which would otherwise be experienced indelivering the fuel at the high pressures necessary and in the shorttime allowed. The charge is determined by the operation of an injectionvalve, which I prefer to yfitl in the pump casin but which may be ttedto the engine cylin er. Theopening of this valve, which is timed tooccur during the final portion of the pump stroke, is controlled by anysuitable mechanism such as a cam and lever, and the period and extent ofvalve opening regulate the charge of fuel injected. The excess of fueldelivered by the pump is' returned to the suction side through a reliefvalve which determines the maximum pressure'of injection and as there isalways some excess to be passed through the relief valve the pressure isthe same for the injection of both large and small quantities of fuel.The opening of the injection valve may be regulated by a sliding camhaving a tapering cam surface of suitable form, so that anl axialmovement of the cam simultaneously adjusts the timing and the period andextent of opening. 0r I may effect the desired adjustment' through thecam operated valve lever byproviding, for example, a movable fulcrum fora jointed lever, the extent .of valve opening varying according to thepositlon of the fulcrum. The timing ofthe valve may be simultaneouslyadjusted by mount-v with reference to the accompanying draw- Figure 1 isa section of pump and valve apparatus 'embodying the principles of myinvention. Fig, 2 is a side elevation of the suction valve cam. Fig. 3is a diagram p villustrating the application of the invention toamulti-cylinder engine. n

A is the pump bodyk or casing, which in the construction illustrated inFig. 1 carries all thevalves` required for the present method ofinjection. 1

B is the pump plunger.

C is the pump 'suction valve operated by the cam c on the cam shaft D.

E is the relief valve.

' F is the injection valve controlled by the sliding cam f on the shaftD.

H is a nozzle in the cylinder cover J, through which nozzle the oil isinjected into the cylinder. Y

K is a pressure gage on the small bore pipe It connecting the nozzle IIto the pump casing.

The pumpy plunger B is driven by the ec rio required for each stroke.The plunger `extends through the gland b in the casing A and its head b2slides in an extension a of the'casing and forms a ball and socket jointwith the end of a short rod b3 on the eccentric Zi. During the suctionstroke of the plunger B the fuel is drawn into the passage a of the pumpcasing from the fuel chamber L, which is kept supplied with fuel throughthe pipe Z, the suction valve C being opened against the pressure of thespring c. Above the short stem of the suction valve is a valve operatingrod .c2 passing through the gland c3 and provided with a head c4connected to the rod c2 at c* sliding in an eX- tension a2 of the pumpcasing and having al spring c5 bearing on its under side. The

' cam c acts on the rod c2 against the spring a5 l plunger B graduallyincreases by reason ofV through the roller c6 on the head c4. Thel camtherefore' may maintain the suction valve C' open after the suctionstroke has 'ended' and the compression begun. The

cam c is so formed as to allow the valve C to close gradually during`the compression stroke so that the fuel pressure in the passage due tothe compression stroke of the the choking action and reaches its maximumonly at or after the complete closing of thev suction valve. The valve Cis held fully open While the concentric cam face c" (-Fig. 2) isoperative, but when the' cam c has turned until a point at about 08 onthe sloping face 09 at the end of the part c7 is reached, the pumpbegins its delivery stroke. Immediately after, the very gradual camslope 01 becomes operative .to .permit the valve C' to slowly'close, andthus produce a choking action upon the fuel. This choking actioncontinues at increasing strength until the-point c is reached at whichcomplete closing of the valve Cl takes place and full fuel pressure isexerted. The valve C remains closed throughout the remainder of thedelivery stroke corresponding to the con- 'centric part 012 of the camc.

The maximuml pressure developed by the pump is determinedby the reliefvalve E on which bears the powerful spring e, thestrength of whichspring can be regulated by screwing the separate valve head e in or outof the plug a3 secured in the valve body A, this plug having arelief'opening e2 in its side through which excess fuel can escape to areservoir or back to the chamber L.4 The spring e is set so as to givethe maximum pressure desired, this pressure being attained before theplunger B reaches the end of its stroke. The remainder of the strokeforces the fuel into the cylinder on the opening of the valve F anddrives the excess fuel l from the (usually a small portion'only) throughthe relief valve. -The maximum pressure may thus be practicallymaintained throughout the injection, owing to the excess supply pumpduring the latter part of its stroke.

The injection Valve F is shown in Fig. l fitted to the pump body, but itmay of course be situated in any convenient position between the pumpand the nozzle H. The cam f opens'this valve at the required point ofthe engine stroke through an arm f on a bracket a4, this arm bearing ona collar .f2 on the valve stem f3, the upper end of which is acted uponvby thespring f4 lplaced in a cup at the end of a bracket a5, the springf* closing the valve when released by the arm f. The timing cam f isarranged to slide v upon the cam shaft D, a groove f5 receiving the camadjustingrmeans. The cam surface varies from one end of the cam to theother so that the points of opening and closing of the valve F can beregulated in accordance with the running of the engine and the power tobe developed. The opening of the valve F always occurs after the closingof the pump suction valve and when the maximum fuel pressure has beenattained so that imme 'ately the valve F is opened the fuel is for dunder the extremely high pressure given by the pump and relief valvethrough the small bore pipe la. and the cylinder nozzle H, the fuelentering the cylinder as a fine spray which instantly vaporizes.

The general operation of the fuel injection mechanism is as follows Thepump plunger B is driven from the engine through the shaft D andeccentric b, the stroke of the pump 4being constant. The suction valve Cis also controlled by the same shaft D through the cam c .which is soformed as to permit the suction valve to close very gradually. 4At eachrevolution, therefore, of the shaft D the pump B on its upward strokedraws in a constant -volume of fluid from the fuel chamber L through thesuction valve C. On the return or compression stroke of the plunger thesuction valve C does not close immediately as would be the case if itwere not under mechanical control. The cam c allows -it to approach itsseat gradually the passage being reduced suiiciently to exercise achoking effect so that the pressure of the fuel in the passage a.gradually rises. At a convenient point in thepump stroke the valve C islallowed to close completely and the pump works in its normal manner. Themaximum pressure of the fuel vis however limited by the springcontrolled relief valve E. After the closing of the suction valve theinjection valve F is Opened by the camA f, the time and period ofopening being variable as already described. The pump plunger continuesits compression stroke whlle the injection valve ing cams ner alrea ydescribed. The small bore tubes for maintaining the openingof the said fis open so that it directly forces the fuel under extremely highpressure through the valve and into the cylinder. l

As applied-to a multi-cylinder engine, .the arrangement illustrateddiagrammatically in Fig 3 may be used, in which the fuel under pressurepasses into a main supply pipe It from which it is supplied to theinjection valves F', one for each cylinder J', these valves beingsituated 'outside the pump body A. They are operated from the slidon thecam shaft D in the manh lead from these valves to injection nozzles inleach of the cylinder heads J. The relief valve E is also shown outsidethe lpump body and the excess fuel flows back into the pump through thesmall pipe e3.

What I claim and desirev to secure by Letters Patent of the UnitedStates is 1. Fuel injecting apparatus for internal combustion engines,comprising a pump adapted to pump a large excess of fuel ateach stroke,mechanically operated valve mechanism for regulating the supply of fuelto the e ine cylinder and for admitting it only during the latter partof the pump compression stroke, a valve allowing escape of fuel duringthe idle portion of the pump compression stroke and mechanical meansvalve, before'the admission of the fuel to the cylinder, so small as toexercise a substantial choking effect on the escape ofthe fuel and forslowly closing the valve so as to increase the choking effect up tocomplete closing and thus gradually to raise the fuel pressure up to thehigh pressure of injection. e

2. Fuel injecting apparatus fol' internal combustion englnes, comprisinga pump adapted to pump a large excess of .fuel at each stroke,mechanically operated valve mechanism for Yregulating the supply of fuelto the engine cylinder and for admitting it only during the latter partof they pump compression stroke, a pump suction valve and means formaintaining the opening of the said suction valve during the idleportion of the compression stroke of the only during the latter partVofthe pump j compression stroke, a Valve allowing escape of fuel duringthe idle portion of the pump compression stroke, mechanical means formaintaining the opening of the said valve, before the admission of thefuel to the cylinder, so small as to exercise a substantial chokingeffect on the escape of the fuel and for slowly closing the valve so asto increase the choking effect up to complete closing and thus graduallyto raise the fuel pressure up tofthe high pressure of injection, and arelief valve between the pump and the engine, set to .open at apredetermined fuel ressure which controls the pressure 4of inn jection.

In testimony whereof l ax my signature in presence of two witnesses. Y

J AMESA MCKECHNIE. vWitnesses:

JAS. 0.*FERGUsoN, W. H. ATKINSON.

